O. aurantiaca (orange).—­A dwarf, cylindrical-stemmed kind, branching freely.  Joints short, 3/4 in. in diameter; cushions of reddish spines, one about 1 in. long, the others shorter; bases of spines enveloped in white wool.  Flowers bright orange, 2 in. to 3 in. across.  This species is a native of Chili, whence it was introduced in 1824.  It should be grown in a warm greenhouse all winter, and placed in a sunny position outside during summer.

O. basilaris (branching at the base); Fig. 76.—­A dwarf, compact plant, of peculiar habit.  Stem short, branching into a number of stout, obovate, often fan-shaped joints, which usually spring from a common base, and curve inwards, suggesting an open cabbage.  Joints 5 in. to 8 in. long, about 1 in. thick, covered all over with dot-like cushions of very short, reddish spines, set in slight depressions or wrinkles.  Flowers of a beautiful and rich purple colour, about 21/2 in. in diameter, and produced in May.  This distinct plant is a native of Mexico, and is of recent introduction.  Plants of it may be seen in the Kew collection.  It is apparently easily kept in health in an ordinary stove temperature along with other Cactuses.  It varies in the form of its joints and in its manner of branching, but it seems never to develop the joints one on the top of the other, as do most Opuntias.  This species is certain to become a favourite when it becomes better known.

[Illustration:  Fig. 76.  Opuntia basilaris.]

O. Bigelovii (Bigelow’s).—­A cylinder-stemmed, tall-growing plant, with a stout, woody stem, bearing a dense head of branches.  Joints 2 in. to 6 in. long, 1 in. to 2 in. in diameter, light green, covered with small tubercles and little spine-cushions, with larger spines 1 in. long.  When wild, the young joints are often shaken off by the wind, and cover the soil around, where they take root or stick to the clothes of the passers-by like burrs.  Flowers not known.  A native of Mexico, where it forms a tree 12 ft. high; it requires stove treatment.  The skeleton of the trunk is a hollow cylinder, perforated with numerous holes, which occur in a regular spiral.  The appearance of a full-grown specimen is very striking, the oval joints, thickly covered with long, needle-like spines, hanging in clusters, more suggestive of spiny fruit than branches.

O. boliviana (Bolivian); Fig. 77.—­Stems 1 ft. high, erect, branching, and composed of roundish, pale green joints, with small, round tubercles, and long, white, flexible spines, sometimes as much as 4 in. in length; cushions about 1 in. apart.  Flowers 11/2 in. across, yellowish.  This is a fat, gouty-looking plant, from Bolivia, requiring stove treatment.  It often assumes a yellow hue on the older joints, even when in good health.

[Illustration:  Fig. 77.  Opuntia boliviana.]